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CAHSEE Math 3.3 Mathematical Reasoning 221 Views

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Description:

Mathematical Reasoning Drill 3 Problem 3. When adding these fractions without finding the lowest common denominator, which of the following is the best estimate of the exact sum?

Language:

English Language

Subjects:

Tags:

Mathematical Reasoning / Estimating unknown quantities

Common Core Standards:

CCSS.Math.Content.HSA-REI.D.11

Transcript

00:03
Here's a shmoopy question you'll find on an exam somewhere in life.
00:07
When adding the fractions 3/7, 5/9 and 6/11 without finding the lowest common denominator,
00:14
which of the following is the best estimate of the exact sum?
00:18
And here are the potential answers...
00:23
Looks like this question is testin’ our estimatin’ skills.

00:27
Basically, we just have to look at each of
00:29
the fractions and come up with a rough estimate for how close they are to 1/9, 1/3, ½ or 2/3.
00:37
3.5 sevenths would be a half, so 3 sevenths is slightly under.
00:42
4.5 ninths would be a half, so 5 ninths is slightly over.
00:49
Anyway. You get the idea.
00:51
The answer is a bunch of halves… or C.
Full Transcript